Sea anchor



Oct. 14, 1969 TAKESHI CHIBA SEA ANCHOR 6 Sheets-Sheet 1 Filed Feb. 27, 1968 INVENTOR. 74(55/7/ 0///@4 Oct. 14, 1969 TAKESHI CHIBA 3,

SEA ANCHOR Filed Feb. 27, 1968 6 Sheets-Sheet 2 INVENTOR. 79/(55/9/ (H/64 Z6720 an; $155, 4 27:; fay

zrzzaowy Oct. 14, 1969 TAKEsm CHIBA 3,472,195

SEA ANCHOR Filed Feb. 2'7, 1968 6 Sheets-Sheet 5 INVENTOR. 74%6514/ CAVE/4 flarea /wt, 62:44:45 i A /a e/v Oct. 14, 1969 TAKESHI CHIBA SEA ancnori 6 Sheets-Sheet 4 Filed Feb. 27, 1968 ,i /as FIG. 7 Has INVENTOR. 7741. .5 6/7/54 0 L 1969 V TAKESHI CHIBA 3, 7 9

SEA ANCHOR Filed Feb. 2'7, 1968 6 h h et 5 INVENTOR. TAX 51 0/454 iff/BNWJ Oct. 14, 1969 TAKESHI CHIBA 3,472,195

SEA ANCHOR Filed Feb. 27. 1968 6 Sheets-Sheet 6 F/GJO United States Patent M 3,472,195 I SEA ANCHOR Takeshi Chiba, Kawasaki-shi, Japan, assignor to Fujikura Parachute Company, Ltd., Tokyo, Japan, a corporation of Japan Filed Feb. 27, 1968, Ser. No. 708,710 Claims priority, application Japan, May 29, 1967, 42/33,652, 42/153,653; Dec. 30, 1967, 42/84,812 Int. Cl. 1563b 21/48 US. Cl. 114-409 Claims ABSTRACT OF THE DISCLOSURE A sea anchor consisting of a canopy of a unique shape and construction, suspension lines, floats and weights on the canopy hem, connectings and a holding pack, and being characterized in that the sea anchor is easy and reliable in handling, launching, deploying in the simplest system, and that the deployed sea anchor body is kept stably in the optimum deploying state in stormy seas.

The present invention relates to a highly effective sea anchor, and more particularly, to the unique shape and rational structures and the reliable deployment system of the sea anchor. Another highly effective sea anchor is disclosed in my copending application Ser. No. 705,085, filed Feb. 13, 1968, and assigned to the same assignee as is the instant application.

Further, the object of the present invention is to provide a sea anchor which supports a vessel on stormy sea, by fastening the tow line of the sea anchor to the bow section of the vessel, keeping the bow of the vessel always against the wind, preventing the vessel from being washed by side waves, and decreasing the rolling and yawing.

Furthermore, the objects and features of the present invention will be emphasized in the following items:

(1) To provide a sea anchor of low cost and with high performance which keeps constantly high drag coetficient when it is used in the sea and can be folded compactly into a specially designed pack, said sea anchor having a drag surface or a canopy made of flexible and durable material, for example, man-made fiber fabrics such as nylon fabrics and the like, said canopy taking a cross shape in its developed plan and being provided with slot vents at the center thereof, small floats at the top side and small weights at the bottom, respectively, in order to impart a buoyancy to the top side and also a gravity to the bottom, thereby the deployment of the canopy being carried out very easily and quickly, and the normal attitude and the full opening shape of the canopy being also kept stable without rotations and revolutions at its deployment state in the water.

(2) To provide a sea anchor having the above-mentioned cross shaped canopy, the height of the top panel of which being formed shorter than the height of the bottom and side panels, thereby, a downward component of the resultant force of the water stream working on the canopy at the deployment state, enabling the deployed canopy staying at an adequate depth in the water and providing a constant effective drag without any submerging accessories such as weight blocks and the like.

(3) To provide a sea anchor, the main body of which can be folded into a specially designed pack compactly, thereby said sea anchor can be launched safely, easily and securely into the water even in poor visibility conditions such as in a dark night, in a dense fog, in a downpour, and in a storm, needless to say in strong wind and high waves.

3,472,195 Patented Oct. 14, 1969 (4) To provide a simplest deployment system of the sea anchor, the canopy will deploy fully in the water in proper order, and rapidly, securely and completely.

The objects, features and advantages of the present invention will be more clearly apparent from the following detailed descriptions with accompanying drawings, in which:

FIG. 1 is an illustration of the general arrangement of the sea anchor of the present invention in the practical use;

FIG. 2 is an illustration of the main body of the sea anchor;

FIG. 3 is a developed plan view of the drag surface, i.e. the canopy;

FIG. 4 is a front view of the canopy which is deployed in the water;

FIG. 5 is a longitudinal sectional view of the main body of the sea anchor which illustrates the function of the drag surface of the sea anchor in the water;

FIG. 6 is an enlarged plan view of the bottom side of the drag surface on which the group of the small weights are attached;

FIG. 7 is a sectional view taken on the line VII-VII in FIG. 6;

FIG. 8 is an illustration of the main parts of the sea anchor, that is, the drag surface, the suspension lines, the connecting webbing, the shackles, the swivel and the pack, and the line-up of which shows the condition just before the packing of the main body into the pack;

FIG. 9 is an illustration of the external appearance of the pack and also shows the relation between the pack, the buoys, the bridle line, the shackles, the swivel, and the rope, and further represents the state of the assembly just before the launching of the present sea anchor systern;

FIG. 10 is a schematic illustration of the pack viewed from the upper side, the flaps of which are closed; and

FIG. 11 is a schematic illustration of the longitudinal section of the pack as shown in FIG. 10..

Referring now to the above-mentioned figures, and embodiment of the present invention is explained in the following:

FIG. 1 shows the general arrangement of the sea anchor of the present invention in the practical use and FIG. 2 shows the main body of said sea anchor, in which the mark V is the wind direction, W is the wavy surface, and A is the main body of the sea anchor. The numeral 1 is the drag surface or the canopy which is made of flexible and durable material such as man-made fiber fabrics, and have a sufiicient drag area. The numeral 2 is the skirt hem of said canopy 1, the numeral 3 indicates the corner notches of the cross shaped canopy 1, and the numerals 2a and 2b are the float band and the weight band which are provided at the top and bottom of said canopy 1, respectively. The numeral 4 denotes the suspension lines which are attached to the top panel of the canopy 1, and 4 denotes the suspension lines which are attached to the both side panels and the bottom panel of the canopy 1. The numerals 5 are the branches of the connecting webbing, 6 is the connecting webbing, 7 and 9 are the shackles, 8 is the swivel, B is the concurrent point of the connecting webbing branches 5, C is the loop end of each connecting webbing branch 5, and O is the center of the canopy 1. The suspension lines are divided into four groups, that is, the groups from the top panel, from the bottom panel and from each side panel, each one end of said suspension line is fastened to the canopy hem 2, and the other end of said suspension line is connected in a group to said loop (2 of the connecting webbing branch 5. The suspension lines 4 attached to both sides and the bottom of the canopy 1 are the same in their lengths, however, the suspension lines 4 are a little longer than said suspension lines 4. A suitable number of the suspension lines 4 and 4' are used to have the canopy 1 remain stably deployed in the water. The suspension lines 4 and 4 are made of sufliciently durable and flexible material such as man-made fiber cord or tape so as to be able to transmit the drag of the canopy 1 to the vessel 16 through the tow line 15. The connecting webbing 6 and their branches 5 are also made of sufliciently durable material such as man-made fiber webbing, and a keeper of the branches 5 is provided at the point B at the end of the webbing 6. The numeral 10 denotes the slot vents at the center of the canopy 1, which regulate the internal pressure of the canopy 1 by opening properly corresponding to the velocity of the water current. The numeral 11 is the connecting cord, one end of which is fastened to the center 0 of the canopy 1 and the other end of which is connected to the cords 12g nearby the small opening 12h on the bottom of the pack 12. The extended portion of said connecting cord 11 is bridle line 13, and further, at the top end of the line 13, buoys 14 are provided. In the practical use in the water, the pack 12 is inside out as shown in FIGS. 1 and 2. The tow line 15 is made of sufficiently strong rope, such as nylon rope, one end of which is fixed to the shackle 9 and the other end of which is fastened to the bow section of the vessel 16.

FIG. 3 shows the details of the canopy 1 in developed plan view, in which the canopy 1 is divided into a large number of small area parts by the frame-work consisting of the stress members 1b, 1c and 1d being made of durable tape material such as nylon tape, and said small parts are covered by thin fabric membranes 1a by means of sewing onto the frame-work, thus giving a high strength/Weight ratio of the canopy 1. The center of the canopy 1 is provided with the slot vents 10, and the top hem and the bottom hem of the canopy 1 are provided with the band 2a and the band 2b, respectively. Said band 2b retains the group of small floats as the same manner of the band 2b. Both ends of the stress members 1b and 1c are connected with suspension lines 4 or 4' as shown in FIG. 6 in detail. According to the above-mentioned construction, the canopy 1 facilitates the repair work when a part of the membrane 1a is torn in the use, the frame-work checking the spreading of the tears. Furthermore, the canopy 1 can be produced at low cost because the developed shape of the canopy 1 consists of orthogonal panels without any curved portions, thus the loss of material can be eliminated in the cutting operation.

The function of the canopy 1 in the water will be explained referring to FIG. in the following:

This figure shows the longitudinal section of the fully opened canopy in the water. The water stream So which equals to the drift speed of the vessel, works on the fully opened canopy 1, as shown in the figure. The partial current 8., of said stream S0 escapes through the vents at the center of the canopy 1 to the back side of the canopy 1, which prevents the occurrence of eddy current and turbulence at the back, and made stable the canopy in good opened shape. The greater part of the stream So runs along the inner side of the canopy 1, and over-flows from the canopy hem 2. The canopy 1 is symmetrical as shown in FIG. 3, however, the height of the top panel is less than that of the bottom panel, so that the quantity of the top overflow S is more than that of the bottom flow S thus the resultant drag force R of the canopy 1 has the downward force T besides the drag D as shown in the figure. The canopy 1 is submerged into the water by said force T, therefore, the sea anchor of the present invention can be kept at the adequate depth in the water by providing with the top panel of proper height. Further, the partial current S of the stream So runs nearby the four corner notches 3 of the canopy 1 to the back side of the canopy 1 at the same speed of the stream So. The rotation and the revolution of the canopy 1 is prevented by the buoyancy of the floats at the top hem'of the canopy, the gravity of the weights at the bottom hem of the canopy, and said partial currents S and S And the eddy current and turbulence at the back side of the canopy are prevented by the current S also the canopy 1 can be retained very stably in a full opening state, the front view of which is shown in FIG. 4.

FIG. 6 shows the detailed construction of a part of the bottom hem of the canopy 1, and FIG. 7 shows the section of said bottom hem on the line VII-VII in FIG. 6. The top hem of the canopy 1 is the same construction as that of the bottom hem shown in FIGS. 6 and 7, in which the floats are substituted for the weights 16. The numeral 17 indicates the loop which is attached to the outer end of each stress member 10 of the canopy 1, and 18 is the seam of the loop 17, thus the suspension line 4 is fixed to the hem of the canopy 1 by the loop 17. The numeral 2b is the weight band of tubular form sewn by the longitudinal seam 20 and holds the small weights 16. The weight band 2b is attached to the canopy hem 2 by the seams 19. The canopy hem 2 is provided with a thick cloth Is by the seams 21 as the reinforcement of the hem. The weights 16 are settled in the band 2b by the seams 19, and the band 211 may be attached independently of the stress of the canopy 1. The both side hems are also provided with the thick cloths 1e without the weight band 212 or float band 2a.

FIG. 8 shows the flaps 12a and 12b of the pack 12. The pack 12 is made of the same material as that of the canopy 1. In the packing operation, the canopy 1 and the suspension lines 4 and 4 are folded into the pack 12, then the flap 12a is closed and the flaps 12b are further closed in the order of the flap numbers. At the same time, the loop 12:: of the flap 12a is inserted through the holes 12 of the flaps 12b. And then the center portion of the connecting webbing 6 is folded in U-shape to be inserted through the loop 122, thus the temporary locking can be carried out, the appearance of which is shown in FIG. 9.

FIG. 10 shows the upper side of the pack 12, the flaps 12a and 12b of the pack are closed. The numerals 12c are drag pockets around the pack body, into which the water flows just after the launching, and the pack 12 becomes difficult to move in the water, thus the deployment of the contents in the pack can be promoted. The numerals 12d are the stays of the pockets 12c, 12 is a hole of each fiap 12b, and 12a is a temporary locking loop provided on the flap 120, that is flap No. 1.

FIG. 11 is an illustration of the longitudinal section of the pack 12 which contains the main body A of the sea anchor, in which the numeral 12h is the small hole on the bottom of the pack, and 12g indicates the bridle line attaching cords fastened around said hole 12h.

The launching of the sea anchor of the present invention can be carried out by the following steps:

The sea anchor arranged as shown in FIG. 9 is placed on the deck of the vessel, one end of the tow line 15 is fixed to the bow section of the vessel, one person holds the pack 12 and the other person holds the shackles 7 and 9, and swivel 8, then they throw them into the water simultaneously. In the case of the small sea anchor, this step can be carried out by one person with his both hands. And then the buoys 14 attached with the bridle line 13 are thrown into the water, further the tow line 15 is paid out. Two buoys are usually employed as one of them may be damaged by the intense wind and waves, and the length of said tow line may be more than twice as long as the Wave length of the sea. In the meantime, the vessel will be drifted by the wind from the launching place, the tension corresponding to the drag force of the sea anchor acts upon the tow line 15, and the bow of the vessel is directed against the wind by said tensile force. Thus the drifting speed of the vessel becomes constant in the equilibrium of the drag force of the sea anchor and the forces acting on the vessel by the wind.

Soon after the pack 12 being launched into the water, some tension will be exerted on the tow line 15, while, the bridle line 13 is effected by the buoyancy of the buoys 14, so that the connecting webbing 6 inserted in U-shape through the fiap loop 12e of the pack 12 is pulled out from the loop 12e, the pack 12 is unlocked, and thus the flaps of the pack are opened. The pack 12 is apt to be retained at the launched position by the buoyancy of the buoys 14 and the drag 0f. the drag pockets 12c, therefore, the suspension lines 4 and 4' and the canopy 1 are pulled out by the webbing 6 one by one from the pack 12, and thus the reliable deployment can be completed in orderly fashion. The canopy 1 is deployed from the skirt hem 2, in which the initial opening of the canopy is carried out and promoted by the float side 2a which floats upwards and the weight side 2b which sinks downwards, the full opening of the canopy 1 is attained in a short time, and the canopy 1 is kept in the normal attitude, thus the rapid, reliable and complete deployment can be carried out orderly as shown in FIG. 1. After the deployment, the fully opened canopy 1 is prevented from the rotation and revolution and is kept stable by the action of the water stream is explained with FIG. 5, thus a high and constant drag coefiicient of the canopy can be obtained. The position of the buoys 14 acts as a guide in confirming the position of the sea anchor and in retrieving said sea anchor on the deck after it is used.

As above-mentioned, the present invention provides not only the highly effective sea anchor at stormy seas, but also the complete and simple deployment system thereof.

What is claimed is:

1. A sea anchor comprising:

a canopy for providing a drag force to support a vessel by a connecting tow line, said canopy having a hem and a cross-sectional shape including a multiple of orthogonal parts;

suspension lines suspending said canopy;

weight and floats being provided on said hem of said canopy;

means including a webbing, shackles and a swivel for connecting said suspension lines to said tow line;

and a holding pack secured to the canopy on the side opposite to the point of tow line connection and providing a deploying system for the foregoing elements.

2. A sea anchor as defined in claim 1 wherein said canopy has a top side on which said floats are provided and a bottom side on which said weights are provided, and wherein said canopy is further provided with slot vents at the center thereof, whereby the deployment of said canopy can be carried out easily and rapidly and be stabilized in the fully deployed attitude without rotation or revolution.

3. A sea anchor as defined in claim 1 wherein the height of the top side of said canopy is less than the height of the bottom side for enabling said canopy to exert, in addition to said drag force, a downward force for keeping said canopy at an adequate depth in the water.

4. A sea anchor as defined in claim 1 wherein the cross-section of said canopy is divided into multiple parts, each having a framework of stress members and a covering membrane, whereby the strength/weight ratio of said canopy is kept high and low cost production is facilitated.

5. A sea anchor as defined in claim 1 wherein said holding pack includes at least one fiapfor temporarily locking said foregoing elements in place when folded into a loop thereof, whereby deployment of said sea anchor can be carried out safetly, easily, rapidly, and completely.

References Cited UNITED STATES PATENTS 898,266 9/ 1908 ROSVOld 114209 2,536,682 1/1951 Frieder et a1. 114209 3,039,419 6/1962 Rimar 114-209 TRYGVE M. BLIX, Primary Examiner 

